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UART4 IRQ Handler not firing

andrew23
Associate II
Posted on September 20, 2014 at 11:50

With my STM32F4 discovery board I cannot get the UART4_IRQHandler to be triggered on incoming serial data. However the USART2_IRQHandler functions as expected and when the data is ready from the UART4 RX data registered and transmitted out it works without a problem, only the interrupt will not work.

Initialisation

++++++++++++++++++++

void uartLink_init(void){

  USART_InitTypeDef USART_InitStructure;

  GPIO_InitTypeDef GPIO_InitStructure;

  NVIC_InitTypeDef NVIC_InitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART4, ENABLE);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART6, ENABLE);

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;

  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;

  GPIO_Init(GPIOC, &GPIO_InitStructure);

GPIO_SetBits(GPIOC, GPIO_Pin_9);

  GPIO_PinAFConfig(GPIOC, GPIO_PinSource6, GPIO_AF_USART6);

  GPIO_PinAFConfig(GPIOC, GPIO_PinSource11, GPIO_AF_UART4);

  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6|GPIO_Pin_11;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOC, &GPIO_InitStructure);

  USART_InitStructure.USART_BaudRate = 115200;

  USART_InitStructure.USART_WordLength = USART_WordLength_8b;

  USART_InitStructure.USART_StopBits = USART_StopBits_1;

  USART_InitStructure.USART_Parity = USART_Parity_No;

  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;

  USART_InitStructure.USART_Mode = USART_Mode_Rx;

 /* USART Rx configuration */

  USART_Init(UART4, &USART_InitStructure);

    /* USART Tx configuration */

  USART_InitStructure.USART_Mode = USART_Mode_Tx;

USART_Init(USART6, &USART_InitStructure);

NVIC_InitStructure.NVIC_IRQChannel = UART4_IRQn;

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

  NVIC_Init(&NVIC_InitStructure);

  /* Enable USART */

  USART_Cmd(UART4, ENABLE);

  USART_Cmd(USART6, ENABLE);

messageStatus = fingerDataWait;

}

+++++++++++++++++++++++++++++

Interrupt

+++++++++++++++++++++++++++++

void UART4_IRQHandler(void){

uint8_t data = USART_ReceiveData(UART4);

USART_SendData(USART6, data);

}

+++++++++++++++++++++++++

Main loop

+++++++++++++++++++++++++

int main(void)

{

prvSetupHardware();

uartLink_init();

power_GPS(POWER_ON);

gps_init();

    

   while(1)                                

   {

     if (USART_GetFlagStatus(UART4, USART_FLAG_RXNE) != RESET)

     {

       uint16_t x = USART_ReceiveData(UART4);

  

       while(USART_GetFlagStatus(USART6, USART_FLAG_TXE) == RESET);

  

       USART_SendData(USART6, x);

     }

   }

++++++++++++++++++++++++

Interestingly with the GPS unit powered and configured as a serial with an interrupt it does not retrun to the main loop when in the debug state. However On the main application which has a freeRTOS implementation it works without problem. This information is possible inconsiquential to the uart4 fault i am having

#irq #stm32f429discovery #uart4
2 REPLIES 2
Posted on September 20, 2014 at 20:13

  USART_ITConfig(UART4, USART_IT_RXNE, ENABLE);

Tips, buy me a coffee, or three.. PayPal Venmo Up vote any posts that you find helpful, it shows what's working..
andrew23
Associate II
Posted on September 21, 2014 at 02:07

Clive1 you are a scholar and a gentleman.

I dont know how I completely overlooked that 100 times from my other example!